Thread: +16.4% LTFT after Injector & MAF upgrade

Yeah, discussing with Will about that right now, will get me some points on the mastercard.

Otherwise, Will mentionned to me that he might've forgotten to adjust the Alternator cut off and that might be what causes the surges decelerating / coming to a stop and the dips with the lope, not sure if I get that, but eh, any one had any of that?

Just giving an update.

Got an HPTuner now, that's fixed. Managed to tune my LTFT's pretty close to 0, still have a bit of fine tuning to do there.

The only thing I'm weirded out by, is my idle is fine, but coasting down and coming to a stop, RPM will surge, sometimes enough to stall. (Although I've only tested that on the first cycle after flashing in the revisions and relearning the trims and driving around for 30 mins or so for the logs.

Running the XP CAM, 4" MAF, #50 INJECTORS, 3.2 PULLEY, 9" OPEN CONE AND CATLESS SD HEADERS.

I can post logs but obviously not the full tune as it is an Overkill base and for obvious reasons.

I'm working with him for the issues, trying to figure it out, but I figured out I should ask back here in the thread I made.

are the ltft's 0 at idle too? you really want them to be -3 to -5 same for cruising. then as close to 0 as possible wot.

im sure hes got the idle raised a bit for the cam right?

Well before I have been running the car with the RPM's at 675 in P/N and 750 in Drive, always worked just fine before I swap the injectors and MAF for the bigger ones.

I revised that myself yesterday and got my P/N at 750 and my Drive at 800, I think.

Here's my latest log for your reference though.
http://s000.tinyupload.com/?file_id=00022773238689033158

Surely you can play it through fast forward and see some idle dips and the behaviors it does.

I still have some MAF tweaking to do, but weather got horrible so I stopped for the night.

i cant se the scan, my excell is acting up.


dont play with the maf. tune the injectors only if the maf was good before hand.

Working on it again, got the coasting down nearly fixed, way better than before.

Did a few WOT runs.

I seem to hit between 11 and 13 psi with the 3.2-GenV, XP cam and catless Headers, without having done any WOT tuning so far, KR seemed to be pretty minimal, the most I saw was a blip of 3*, time to work that out now.

try taking a degree or 2 out of wot timing in the rpm range you have kr in.

Something weird I noticed today by adding Injector duty cycle on my HPT charts...

Is it possible to hit 117% duty cycle with #50 injectors and a 3.2 pulley on a Gen V ?
I used to see close to those duty cycles on the stockers on a 3.5 pulley / cam, didn't expect to see those out of the 50's.

Here's a log for the curious ones.
http://s000.tinyupload.com/?file_id=84674890568243010971

Also, from a dig, I can hit 13 ish PSI of boost, no KR at all, 0 to 80 ish kph or more, if from a dig.

But I did some random pull, rolling from maybe 90-100 ish kph, and it spiked between 2 and 4* of KR, less boost, less RPM, not even WOT.
There are instances of both issues in the log.

Still playing around with timing and my trims too.

kr will always show its self more in 2 nd gear.

I've never installed bigger injectors on a 3800 but it likely has something to do with how you have the injector information put into the tune and if you have them scaled in any way.

I could see 117% duty cycle on stock injectors with those mods but with 50lb injectors there is no way it's ever going to be that high. Maybe 75-80% in the upper rpm range with the power you are putting down.

That's what I'm finding weird, they're pretty big injectors for a 3.2 Gen V set up.

Everyone says that 04+ cars don't read IPW correctly so I wouldn't go by that. I would hit 24ms on a stock 05 GTP. What gets me is the coasting down. On 04 only the alternator has a 1 way clutch (over running) and it is supppsed to freewheel if there isn't a load on the alternator and the engine RPM falls faster than the alternator would. Do you have the over running clutch or just a regular bolt on pulley? My 05 on E85 will hit 34.5ms IPW on a hard run with a 11:1 AFR so I seriously doubt you are maxing out the injectors. Here in a few days when the weather gets better I will connect an Oscope to my injectors and see what the IPW is compared to what DHP is saying. It seems no one knows even what the time constant is supposed to be.

Jeff

Haha, well I would doubt maxing out #50 if fellows run similar, or smaller pulley's set up than mine on 42.5'er.
Not sure what the pulley on the alternator is, though. It's an early production car, so might be anything they had then, still factory.

I guess I just need to fine-tune my timing and trims at WOT to tune out KR on the second gear. (My trims are most of the time in the -3 +3 range, so it's getting there.)

Right now, first gear pulls from a stop, it runs hard without knock, my issue is mainly when driving above 70-80kph, whenever I get on the gas, not even wot, I see some KR spikes, even saw, I think it was 4.9* at one point, never too sure, I barely if ever drive that car faster than 80-100, since work only requires me to drive in its knock-free zone.

I've got, hmm, 1-2 years old AL104's with maybe, max 5 or 8k KM, they're gapped at 0.050. They should technically be enough for a 3.2 Gen V - Headers - XP car, right ?

whats your wot timing. second gear always makes kr when first dont, so you need to tune the timing so it kr free in second gear. you wont notice the timing drop in first gear.

your trims, in a perfect world -5 or lower idle and cruising, and it should drop close to zero wot. i like to set mine to -1. anything is close enough to me. leaves it a bit rich. nailing dead zero is like hitting the lotto especially if using DHP.

WOT Timing is 16* right now

LTFT's, for example, not done tuning them though.


The KR blip, highest I saw, with the pulley.

well now its the pulley and timing game then. id take out a degree at a time till its kr free.

might be best to just pulley up. 3.4 and a cam with nothing else seems to be the safe place for most. most of the time the most timing you can run the better, boost dont mean more power, its the restriction of flow.

i only make 8 psi on a 3.2 pulley and im bottom swapped. ic heads and rockers. all help it flow better.

Well I'm only lacking the intercooler at this point.

But true, with catless headers, the XP cam, I did reach up to 13 psi or so, from an HPT log I had, that pull had no KR, though.